fix: not clearing local data when logging out while sync is running (#20646)

mobile/lib/domain/utils/background_sync.dart

@@ -37,7 +37,7 @@ class BackgroundSyncManager {
     this.onHashingError,
   });
 
-  Future<void> cancel() {
+  Future<void> cancel() async {
     final futures = <Future>[];
 
     if (_syncTask != null) {
@@ -52,7 +52,11 @@ class BackgroundSyncManager {
     _syncWebsocketTask?.cancel();
     _syncWebsocketTask = null;
 
-    return Future.wait(futures);
+    try {
+      await Future.wait(futures);
+    } on CanceledError {
+      // Ignore cancellation errors
+    }
   }
 
   // No need to cancel the task, as it can also be run when the user logs out

mobile/lib/main.dart

@@ -83,7 +83,6 @@ Future<void> initApp() async {
   };
 
   PlatformDispatcher.instance.onError = (error, stack) {
-    debugPrint("FlutterError - Catch all: $error \n $stack");
     log.severe('PlatformDispatcher - Catch all', error, stack);
     return true;
   };